Theorem mobii 2114

Description: Formula-building rule for "at most one" quantifier (inference form). (Contributed by NM, 9-Mar-1995.) (Revised by Mario Carneiro, 17-Oct-2016.)

Hypothesis

Ref	Expression
mobii.1	⊢ (𝜓 ↔ 𝜒)

Assertion

Ref	Expression
mobii	⊢ (∃*𝑥𝜓 ↔ ∃*𝑥𝜒)

Proof of Theorem mobii

Step	Hyp	Ref	Expression
1		mobii.1	. . . 4 ⊢ (𝜓 ↔ 𝜒)
2	1	a1i 9	. . 3 ⊢ (⊤ → (𝜓 ↔ 𝜒))
3	2	mobidv 2113	. 2 ⊢ (⊤ → (∃*𝑥𝜓 ↔ ∃*𝑥𝜒))
4	3	mptru 1404	1 ⊢ (∃*𝑥𝜓 ↔ ∃*𝑥𝜒)

Syntax hints:   ↔ wb 105  ⊤wtru 1396  ∃*wmo 2078

This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-ia1 106  ax-ia2 107  ax-ia3 108  ax-5 1493  ax-gen 1495  ax-ie1 1539  ax-ie2 1540  ax-4 1556  ax-17 1572  ax-ial 1580

This theorem depends on definitions:  df-bi 117  df-tru 1398  df-nf 1507  df-eu 2080  df-mo 2081

This theorem is referenced by:  moaneu  2154  moanmo  2155  2moswapdc  2168  2exeu  2170  rmobiia  2722  rmov  2820  euxfr2dc  2988  rmoan  3003  2rmorex  3009  mosn  3702  dffun9  5346  funopab  5352  funco  5357  funcnv2  5380  funcnv  5381  fun2cnv  5384  fncnv  5386  imadif  5400  fnres  5439  ovi3  6141  oprabex3  6272  axaddf  8051  axmulf  8052  frecuzrdgtcl  10629  frecuzrdgfunlem  10636  fsum3  11893